1. Field of the Invention
The present invention relates generally to a vehicle powertrain system and, more particularly, to a hybrid powertrain system employing at least two prime movers and a twin clutch transmission.
2. Description of the Related Art
Various types of twin clutch transmissions have been proposed and put into practical use, particularly in the field of wheeled motor vehicles. Traditional twin clutch transmissions are of a type in which gears are parted into two groups, each group having an individual main clutch, so that the operative condition of each group of gears is carried out by selectively engaging a corresponding main clutch. Twin clutch transmissions are used in vehicles to improve the transition from one gear ratio to another and, in doing so, improve the efficiency of the transmission.
Hybrid vehicle powertrain systems employing two or more prime movers are also known in the art. A typical hybrid powertrain system includes an internal combustion engine that is strategically operated in combination with an electric motor to provide driving torque to the wheels of a vehicle. Among other features, hybrid powertrain systems improve vehicle fuel economy by allowing a reduction in the displacement of the internal combustion engine and by recapturing and using kinetic energy lost during vehicle braking in a conventional powertrain system.